Tag: OM-PGD

Photo Report – Let L-410MA Turbolet, OM-PGD

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By me
All photos me too, copyrighted

The sudden appearance of An-2 9A-DIZ at Lučko – usually a sign of impending parachute activity – should have warned me that a foreign visitor, hired for the same purpose, would probably follow suit. It didn’t, so I was pleasantly surprised this morning to come across a sharp-looking Turbolet visiting the field for the first time, just waiting – begging 😀 – to be photographed :D. Despite being a relatively common aircraft in these parts, I was naturally at it within minutes and soon discovered that it was not as ordinary as I had first thought…

Registered in Slovakia, OM-PGD was – like OK-SAS, the last Turbolet to visit – in town for some parachute ops, substituting for AK Zagreb’s poor old Cessna 185 which, more than a year after its unfortunate propstrike, is still nowhere near airworthy status. And while externally identical at a glance to any other Turbolet out there, PGD is in fact a rather rare early MA model, one of the first Turbolet marks produced in any significant quantity – and one of the few non-STOL models still flying today…

Designed from the outset to be powered by the Czech Walter M601 turboprop – the PT6 of the Eastern Block – that was in development at the time, the first production L-410s got off to a slightly more ironic start when M601 development delays and problems forced the temporary selection of another engine. The only one suitable and available was the PT6 itself, so to avoid any further disruptions, the first production series – the 28-strong L-410A – was fitted with two PT6A-27s and sent on its way.

In the mean time, the basic M601 design had matured into the slightly larger and more powerful 700 HP M601A which – coupled with an Avia V508 three-blade propeller – was deemed ready for the L-410. In this form the aircraft became the slightly-less rare L-410M, of which about 108 were produced.

What can today be considered as the “bog standard” Turbolet – the UVP – differed in some respects from the M model from which it was developed, including a slightly longer fuselage, larger wings, a taller vertical stabilizer and 730 HP M601B engines. And while the M didn’t have what you’d describe as a long take-off run, the UVP was the first model to introduce the STOL capability for which the design is now famous (500 m with a 1800 kg payload!).

The MA though was a mix of the two worlds, being the basic L-410M powered by the UVP’s M601B engines. Where it fits into the design lineage I’m not sure, but given that almost all M versions flying today are MAs, it is safe to assume that this version is a retrofit. Be that as it may, it represents the last of the L-410 “originals” and was sufficiently rare to get my full attention :D.

Even when looking at it for awhile, it's hard to distinguish it from the "normal" UVP... only the slightly shorter fuselage is a giveaway...

That's a pretty large behind! 😀 Despite its questionable aesthetics when viewed from this angle, the fuselage is commodious and very practical - and I'm told well suited for and liked by parachutists
Blending well with the dull overcast... like on many parachute versions, the standard doors had been removed and fitted with a much more practical "garage door"
Ready to go off road :). The unusual landing gear bay arrangement frees up space within the cabin - making it simpler and structurally sounder - while also allowing the main wheels to have a wider track, which is very useful on uneven terrain
To handle the rough stuff, L-410s of all marks are fitted with large low pressure tires and very, very powerful "packet" disk brakes. Unlike brakes on smaller aircraft - which usually have only one small brake pad and caliper - the "packet" brake consists of a full-size circular pad, providing friction across the whole disk. To press it in, the L-410 uses seven pistons, which make the brake forces very strong and enable a lot of hard breaking before the brakes lock up. Note also the red line painted across the wheel and tire: this is a handy way of checking whether the tire is properly inflated when you don't have a manometer handy. Should the tire become significantly under-inflated, on takeoff and landing it would start to rotate around the wheel itself, moving the mark out of alignment
Though not as extensive as on other STOL aircraft, the windscreen provides a very good field of vision for both crew. Windscreen wipers are a must for all-weather operations
Two of the L-410's unusual features are the copilot side door, just below the side window, and the confusing black fuselage stripe. This thin layer of rubber is necessary protection of the fuselage - and especially the joint between two fuselage sheets - from bits of ice shot off the prop when its deicer is in operation. On many light aircraft - I've especially noted this on Piper twins - this protection is a metal sheet and is usually painted over so it is not easily noticeable
A generation apart... one of the L-410's design aims was to replace the An-2 in many of its transport roles; but it ended up just supplementing it, as the venerable Anushka almost outlasted the L-410 in production...